The field of the present invention is that of headlights and, more specifically, that of motor vehicle headlights.
Motor vehicle headlights generally comprise a reflector, in which a light source and means for controlling the shape of the beam to adapt the beam to the driving conditions are disposed.
It is known for a cut-off bar (or blade) to be used that allows various occultation phases of the light beam to be provided. The cut-off bar is actuated electrically in order to move, on command, between at least two angular positions, in which it more or less occults the light beam. This allows the range of the headlight to be limited, for example to that of the dipped beam, called code position, so as not to dazzle oncoming drivers, or also to that of the main beam, called road position, in which there is no occultation.
The devices of the prior art that control the position of the cut-off bar are generally made up of an actuator motor associated with a sensor of the position of the cut-off bar or a stop that defines the rest position of the cut-off bar. For safety reasons, this rest position is associated with the code position in order to prevent oncoming drivers from being dazzled in the event of a failure of the device for actuating the bar. The return to the stop position or to the extreme position is generally provided by a spring.
In order to produce the actuator motors, the use of an electromagnet is known that exerts, against a return spring, an attraction force on a movable element connected to the cut-off bar. It further comprises a metallic casing that forms a cradle for the electromagnet and that provides its magnetic loop. The electromagnet comprises an induction coil formed by turns, which are supplied with electric current in order to actuate the motor, and a ferromagnetic core that is placed at the centre of the coil. This core is longitudinally fixed in the coil and is used to act as a point of attraction for the movable element when the coil is powered.